German Pat. No. 945,583 discloses a space heater of the above-mentioned type having a vertically arranged grid-like heating body mounted in a shielding housing having walls which at least partially include a mesh-like grid. In this space heater, the fresh air reaches the interior of the housing through the mesh-like grid whereby the air is swirled by the mesh-like grid so that the air can better take up the heat radiated by the hot wires. In the housing, the air passes through the grid-like heating body, moves upwardly on the rearward side of the heating body and is projected outwardly to the ambient from an upper grid in a jet-like manner.
However, the space heater disclosed in the above mentioned German Patent cannot be utilized in damp rooms such as a bathroom, shower room or the like. As a space heater, the apparatus has a large discharge because of the way it must be configured to provide the required contact safety. The fresh air flowing into the apparatus is swirled simultaneously from all sides such that the heated air does not flow outwardly therefrom in a directed and quieted flow. The apparatus therefore requires that free air can enter at all sides so that the apparatus cannot be mounted on a wall or utilized as a wall unit without modification.
U.S. Pat. No. 3,829,656 discloses a space heater wherein the heating elements are defined by horizontal heating rods which are arranged one above the other and are mounted in a closed housing. This housing is surrounded by an outer open housing into which fresh air flows from below. After warming, the air flows out through an upper outlet opening. Because of the arrangement of two metal housings, one disposed inside the other, substantial construction costs are incurred. Further, the heating elements do not directly warm the air because of their arrangement inside of a closed housing so that a long heating time is required.
A low pressure temperature heating apparatus is known having a flat frame-like housing which is made from formed pieces of enamelled sheet metal. The heating apparatus functions pursuant to the principal of a free standing heating wall which has neither air entry openings nor air exit openings. The heating apparatus functions in a manner such that the surrounding air reaches all sides of this heating wall in the same manner. For this purpose, the surface of the heating apparatus is of a raster-like construction by means of which an aimed direction of flow of the air flowing upwardly from below is prevented directly in the region of the heating elements. This apparatus is unsuitable for placement in rooms wherein sprayed water can impinge directly thereon because the heating wires are only surrounded with glass fibers.